1. Field of the Invention
The present invention relates to a new way of removably fixing a dental instrument into the head of a handpiece.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
Dental instruments, dental burs or endodontic instruments, for example, are generally made up of an active part and a shank (see FIG. 1) for fixing them into handpieces, of the right-angle handpiece type or contra-angle handpiece type.
There is a standard defining the shank for instruments used at low speed. According to this standard, the shank of the instruments is cylindrical and has a groove (a) for axially retaining them and a flat (b) for rotationally driving them.
Numerous fixing devices for these instruments have been described. They force the user to find the angular position of the instrument such that the flat can engage in the combined shape of the latching device while at the same time operating a push-button system able to open the latching device, which collaborates with the groove of the shank of the instrument.
Devices such as the one described in French patent FR 2 555 041 make it possible to dispense with the need to operate a push-button, but there is still a need to find the correct angular position of the instrument in order to engage the flat.
These operations force the user to pick up the instrument in his or her hand, even though this instrument has been sterilized and is generally placed on a stand. Now, the search for the best possible conditions of asepsis during interventions demands that these sterilized instruments must not be touched before they are used.
The chief objective of the invention is to alleviate the aforementioned disadvantages.